1. Field of the Invention
The present invention relates generally to a control method and swing mechanism for an infant and child swing, especially to a swing can move freely by inertia force and gravity force after passed a reference point in a first direction and before returned to the reference point for saving energy.
2. Description of the Related Art
Traditional powered swing either for baby or child, has an example disclosed in U.S. Pat. No. 5,846,136, which uses a cam-like member associated with a spring to drive the swing arm thereof forth and back. However, the mechanical energy is always wasted too much between the ineffective vibrations of the spring. The preselected swing amplitude may also not be obtained with accurate and consistent.
U.S. Pat. No. 5,846,136 provided a method for controlling the amplitude of a swing accurately and consistently, which includes the steps of monitoring the current swing amplitude, generating a swing amplitude signal which is representative of said current swing amplitude, comparing the current swing amplitude when the swing changes direction with a preselected maximum swing amplitude; and, adjusting the output power of the motor when the current swing amplitude is not substantially equal to the preselected maximum swing amplitude. The swing cycle is monitored and the energy produced by the swing motor to drive the swing is reviewed for adjustment no less frequently than once each swing cycle, thereby improving the accuracy and consistency of swing height. However, as the swing is used for amusement not for industrial instrument, the control method of U.S. Pat. No. 5,846,136 is too complex to a child or baby swing.